Multi-electrode gaseous-discharge tube circuits



July 26, 1955 D. G. A. THOMAS ETAL 2,714,179

MULTI-ELECTRODE GASEOUS-DISCHARGE TUBE CIRCUITS Filed Feb. 19, 1952 5 Sheets-Sheet l F/GZ. [3/ 60v lNVENTOR BY R Gm ATTORNEY July 26, 1955 D. G. A. THOMAS ETAL 2,714,179

MULTI-ELECTRODE GASEOUS-DISCHARGE TUBE CIRCUITS 5 Sheets-Sheet 2 Filed Feb. 19, 1952 N VE N 7' CR6 77/0M/75,

ATTORNEY July 26, 1955 D. G. A. THOMAS ET AL 2,714,179

MULTI-ELECTRODE GASEOUS-DISCHARGE TUBE CIRCUITS Filed Feb. 19, 1952 5 Sheets-Sheet 3 B) QM ATTORNEY United States Patent MULTl-ELECTRQDE GASEOUS-DISCHARGE TUBE CIRCUITS David Gurney Arnold Thomas, Deer-burst Walton, near Gloucester, and Edmund Harry Cooke-Yarborough, Faringdon, England, assignors to The National Research Development Corporation, London, England Application February 19, 1952, Serial No. 272,312

7 Claims. (Cl. 315-163) This invention relates to electrical circuit arrangements using multi-cathode gaseous-discharge tubes. Circuits according to the invention have applications in. electronic calculating machines.

Multi-cathode gaseous-discharge tubes, sometimes referred to as cold cathode counting tubes or polycathode glow tubes, have been described in the literature including an article Polycathode glow tube for counters, by J. 1. Lamb and J. A. Brustman. (Electronics, Mc- Graw-Hill Publishing Company, November 1949; pages 9296), an article The; Damona. new c'o'ld. cathode counting tube, by R. C. Bacon and I. R; Pollard (Electronic Engineering, vol. 22, No. 267, May 1950, pages 173477 and an article Multicathdde gas-tube counters, by G. H. Hough and D. S; Ridler (Electrical Communication, vol. 27, No; 3, September 1950, pages 214--226).

It is the urpose of this invention to provide an electrical circuit for operating a first or receiving multicathode gaseous discharge tube according to a number stored on a second or sending multi-ca-thode gaseousdischarge tube. Such an electrical circuit is hereinafter referred to as a transfer circuit.

A number, represented by the position of the discharge in the sending tube, may be added to a numbersimilarly represented in the receiving tube. Alternatively the compiement of a number in the sendin tube may be added to a number in the receiving tube, this being equivalent to a subtraction operation. I

The transfer circuit according to: the invention comprises a multi-cathode gaseous-discharge. tube (sending tube) pulse generating means to cycle the discharge in the sending tube, means for deriving a pulse (control pulse) when that discharge reaches the output electrode f the sending tube andswitch means operated by the control pulse for switching a pulse tr-ain to another multicathode gaseous-discharge tube (receiving tube) whereby a count is derived in the receiving tube dependent upon the count in the sending tube.

in another aspect a transfer circuit according to the invention comprises a sendingmulti-cathode gaseous discharge tube, pulse generating means connected to move the discharge in said tube, means producing a pulse when said discharge arrives at the' zero cathode of said tube, a switch operated by said pulse connected to. switch'pulses of a pulse train which occur'befdre said'pulse down a first channel and those which occur after said control pulse down a second channel; a eceiving mun-icathode gaseous-discharge tube and a switch for connecting the" receiving tube to either the first or secondchannel.

A transfer circuit embodying the invention is now described with reference to the drawings whereinz Fig. 1 shows diagrammatically the arrangements of the electrodes of a decimal type of multi-cathodegaseousdisc harge tube.

Fig. 2 shows pulse forms for operating the tube of Fig. 1.

Fig. 3 shows a diagrammatic form of the tube described with reference to Fig. 1 and as used in the circuit of Fig. 4.

Fig. 4 is a circuit diagram of the transfer circuit.

Fig. 5 shows waveforms at points in the circuit of Fig. 4.

In Fig. 1, nine main discharge cathodes 1 and an output or zero cathode 2 are equally disposed round a central anode 3, and a common connecting wire 4 joins all the cathodes 1. Between adjacent main cathodesand between the zero or output cathode and adjacent main cathodes there are first guide cathodes 5 and second guide cathodes 6 and these have common connecting wires 7, 8 respectively. Leads 9, 1t), 11, 12 are taken from the electrodes as shown. For normal operation the cathode 2 is taken through a resistance to earth or to a small bias potential and the cathodes 1 are earthed. In a typical case the electrodes 5, 6 rest at 60 volts positive and the anode is connected through a resistance of 1 M9 to a 350 volt H. T. supply.

On first switching on a tube such as shown in Fig. 1 a discharge is set up between an anode and one of the cathodes 1 or 2. To move the discharge to the next cathode pulse pairs of the form shown in Fig. 2, are applied to the guide electrodes. Pulse 13, of volts negative swing and 1.5 ms. duration is applied to guide electrodes 5 thus causing the discharge to move from the cathode on which it initially rested on the adjacent electrode 5. At the end of the pulse 13, a pulse 14, similar to pulse 13, is applied to guide electrodes 6 to move the discharge on to the adjacent electrode 6 which has become more negative than any adjacent electrode or cathode. At the end of pulse 14 the discharge moves to the cathode 1 adjacent to the electrode 6, and thus the discharge has completed one step between adjacent cathodes. It is not necessary for the pair of pulses 13 and 14 to overlap, but it is important that there should be no time interval between the end of pulse 13 and the start of pulse 14 in excess of the deionisation time of the tube. Pulses 13 and 14 are conventionally referred to, as A and B pulses respectively.

In Fig. 3 a tube 15 is represented diagrammatically. Electrode 16 is the anode, electrode 17 is the output or zero cathode having an output terminal 13 and a resistance 19 to earth. The main cathodes connected to earth are identified by electrode 20, the first guide cathodes by electrode 21 and the second guide cathodes by electrode 22.

In the operation of a tube such as tube 15 a number n may be passed for storage by applying 11 pairs of pulses such as pulses 13, 14 of Fig. 2 so that the discharge advances n steps.

In Fig. 4 the main components of the circuit are a sending address 30, a trigger neon 31, triggered by a pulse from the zero cathode 32 of the tube 33 in the sending address, a double triode switch 34 operated when the neon 31 is triggered and restored on completion of the transfer operation, a receiving address 35 having a tube 36, and a pulse generator 37 to feed operating pulse trains to the other components of the circuit.

The pulse generator supplies, by connection 38, a train of ten pulses to the first guide electrode 39 of tube 33; by connection 40, a train of ten pulses to the second guide electrode 41 of tube 33; by connections 42, a train of ten pulses, similar and coincident to those in connection 40 but at a different D. C. level, to the cathode 52 of valve 43 in the switch 34; and by connection 44, a train of nine pulses, corresponding in time to the last nine of the pulses in connection 38, to the first guide electrode 62 of the tube 36. The waveforms in connections 38, 40, 42 and 44 are shown in Figs. (a), 5(5), 5(g) and 5(h) respectively. The circuit is now further described for the typical case of a count of three, stored in the sending address 30, which is to be transferred to the receiving address 35.

The first seven pulses shown in each of Figs. 5(a) and 5(b) circulate the discharge on the tube 33 from the third main cathode to the Zero cathode 32 to set up a voltage in the resistance 45 which is transmitted to the trigger electrode 46 of the neon 31 by Way of coupling condenser 47 so as to trigger the neon 31 (see Fig 5(c)). The remaining three pulses of Figs. 5(a) and 5(b), circulate the discharge on tube 33 to reach its initial position on the third main cathode. The triggering of neon 31 causes the potential of the cathode 48 to rise (see Fig. 5(d)) so that the grid 49 of the double triode switch 34 rises to divert the current flow through the switch 34 from the anode 50 to the anode 51. The switch 34, which is being fed with pulses as shown in Fig. 5(3) at the cathode 52 of valve 43, therefore transmits the first seven pulses via anode Stl and the remaining three pulses via anode 51. A rectifier limiter arrangement comprising rectifiers 53, 54, S5, 56 limits the voltage variations of anodes 5 and 51 between sixty volts positive and sixty volts negative. The voltages in the anodes 50 and 51 are fed to a change-over switch 57 by connections 58 and 59 respectively. The switch 57 is shown in the add position, that is, the anode 51, which carries three pulses, is connected by connection 60 to the second guide electrode 61 of the receiving address 35. These three pulses, together with the last three pulses as shown in Fig. 5 (h) which are connected to the first guide electrode 62 of the receiving address 35, cause the discharge in that address to move three steps; that is the count of three in the sending address has been added to the count in the receiving ad dress.

If, before the transfer operation had commenced, the switch 57 was placed in the alternative position to that shown, i. e. in the completement position, the seven pulses at anode 59 would be connected to the second guide electrode 61. The first of these pulses causes the discharge in the receiving address 35 to move backwards relative to the normal direction of operation, on to one of the electrodes of guide electrode 61, and subsequently, at the end of the pulse, to revert to its original position. The first six of the pulses shown in Fig. 501) thereafter pair with the remaining six pulses from anode 50 to move the discharge on the receiving address by six steps; that is the count in the sending address is added as a completement on nine to the receiving address. This operation is the equivalent of subtracting a count of three from the receiving address.

The H. T. supply to the neon 3%. is pulsed by means of an electronic switch in the pulse generator, shown by switch 63, so as to be on only when the transfer circuit is called upon to perform a transfer operation. In this way, the switch 63 resets the circuit after use and minimises the chances of spurious triggering that would preset the double triode switch.

In order to clear to zero the sending address 30 or to zero the tube 33 after switching on, a connection 65 is provided between the complement side of switch 57 and the second guide electrode 4i of tube 33. A double switch, consisting of contact 66 in connection 65 and contact 67 in connection 40', both shown in the unoperated position, may be operated to provide this clear to zero facility. Pulses, as shown in Fig. 5(e), are then paired with a pulse train, such as shown in Fig. 5(a) to circulate the discharge in the tube 33; the pulses as shown in Fig. 5(b) being removed. The circulation of the discharge ceases when the zero cathode of the tube 33 is reached.

A list of component sizes suitable for a circuit such as that of Fig. 4 is given below:

Resistances:

No. 45 180 K No. 68 l M No. 70 l M No. 71 33 K No. 72 27 K No. 74 100 No. 75 10 M No. 76 l M No. 77 l M No. 78 10 K No. 79 l M No. 80 180 K No. 31 Condensers:

No. 45 1500 p No. 69 1500 p No. '73 4700 p We claim:

1. A transfer circuit comprising a first multi-cathode gaseous-discharge tube, pulse generating means to cycle the discharge in said tube, means for deriving a control pulse when that discharge reaches the output electrode of said tube and switch means operated by the control pulse for switching a pulse train to a second multi-cathode gaseous-discharge tube whereby a count is derived in the second tube dependent upon the count in the first tube.

2. A transfer circuit according to claim 1 wherein said switch means operates to interrupt the pulse train to the second tube whereby the discharge in the second tube is moved by an amount the discharge moves in the first tube in reaching its zero cathode.

3. A transfer circuit according to claim 1 wherein said switch means operates to connect the pulse train to the second tube whereby the discharge in the second tube is moved by an amount depending upon the amount the discharge moves in the first tube after passing the output cathode.

4. A transfer circuit comprising a first multi-cathode gaseous-discharge tube, pulse generating means connected to move the discharge in said tube, means producing a pulse when said discharge arrives at the zero cathode of said tube, a switch, operated by said pulse and connected to switch pulses of a pulse train which occur before said control pulse down a first channel and those which occur after said control pulse down a second channel, a second multi-cathode gaseous-discharge tube and a switch for connecting the second tube to either the first .or second channel.

5. A transfer circuit comprising first and second multi-cathode gaseous-discharge tubes of the type having first and second groups of transfer cathodes each group having ten cathodes and wherein the discharge is moved by the application of pulse trains, conveniently called A and B pulse train, to said first and second group of transfer cathodes respectively, means for feeding ten pulses of an A pulse train and ten pulses of a B pulse train to the first and second groups of transfer cathodes respectively of said first tube, a triggered gaseous-discharge tube connected to be fired by a pulse generated at the zero cathode of the first tube, means for deriving a switching potential from said trigger tube when it conducts, a changeover switch connected to be operated by said switching potential, means for feeding ten pulses of a B pulse train coincident with the B pulses fed to the second transfer cathode group to the input of said switch, means for connecting either one or the other of the outputs of said switch to the second group of transfer cathodes of said second multi-cathode gaseous-discharge tube and means for feeding nine pulses of an A pulse train to the first group of transfer cathodes of said first multi-cathode gaseous-discharge tube so that those nine pulses are suited to pair with the last nine pulses fed to the input of said switch.

6. A transfer circuit according to claim 5 having means for disconnecting said ten pulses of a B pulse train fed to the second group of transfer cathodes of said first Inulti-cathode tube and means for connecting in their place those pulses in an output from said changeover switch.

7. A transfer circuit comprising a first multi-electrode gaseous-discharge tube, pulse generating means to cycle the discharge in said tube, means for deriving a References Cited in the file of this patent UNITED STATES PATENTS Lyman June 14, 1949 Wales Oct. 3, 1950 

